/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights
 * reserved.
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 * modification, are permitted provided that the following conditions
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 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
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 * 4. The names "Xerces" and "Apache Software Foundation" must
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 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, International
 * Business Machines, Inc., http://www.apache.org.  For more
 * information on the Apache Software Foundation, please see
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 */

package com.flickr4java.flickr.util;

/**
 * This class provides encode/decode for RFC 2045 Base64 as defined by RFC 2045, N. Freed and N. Borenstein. RFC 2045: Multipurpose Internet Mail Extensions
 * (MIME) Part One: Format of Internet Message Bodies. Reference 1996 Available at: http://www.ietf.org/rfc/rfc2045.txt This class is used by XML Schema binary
 * format validation.
 * <p>
 * 
 * This implementation does not encode/decode streaming data. You need the data that you will encode/decode already on a byte array.
 * <p>
 * 
 * This is the latest pre commons-codec version of Base64.
 * 
 * @author Jeffrey Rodriguez
 * @author Sandy Gao
 * @version Base64.java,v 1.8 2001/05/29 22:19:01 neilg Exp
 */
public final class Base64 {
    static private final int BASELENGTH = 255;

    static private final int LOOKUPLENGTH = 64;

    static private final int TWENTYFOURBITGROUP = 24;

    static private final int EIGHTBIT = 8;

    static private final int SIXTEENBIT = 16;

    static private final int SIXBIT = 6;

    static private final int FOURBYTE = 4;

    static private final int SIGN = -128;

    static private final byte PAD = (byte) '=';

    static private final boolean fDebug = false;

    static private byte[] base64Alphabet = new byte[BASELENGTH];

    static private byte[] lookUpBase64Alphabet = new byte[LOOKUPLENGTH];

    static {

        for (int i = 0; i < BASELENGTH; i++) {
            base64Alphabet[i] = -1;
        }
        for (int i = 'Z'; i >= 'A'; i--) {
            base64Alphabet[i] = (byte) (i - 'A');
        }
        for (int i = 'z'; i >= 'a'; i--) {
            base64Alphabet[i] = (byte) (i - 'a' + 26);
        }

        for (int i = '9'; i >= '0'; i--) {
            base64Alphabet[i] = (byte) (i - '0' + 52);
        }

        base64Alphabet['+'] = 62;
        base64Alphabet['/'] = 63;

        for (int i = 0; i <= 25; i++)
            lookUpBase64Alphabet[i] = (byte) ('A' + i);

        for (int i = 26, j = 0; i <= 51; i++, j++)
            lookUpBase64Alphabet[i] = (byte) ('a' + j);

        for (int i = 52, j = 0; i <= 61; i++, j++)
            lookUpBase64Alphabet[i] = (byte) ('0' + j);
        lookUpBase64Alphabet[62] = (byte) '+';
        lookUpBase64Alphabet[63] = (byte) '/';

    }

    protected static boolean isWhiteSpace(byte octect) {
        return (octect == 0x20 || octect == 0xd || octect == 0xa || octect == 0x9);
    }

    protected static boolean isPad(byte octect) {
        return (octect == PAD);
    }

    protected static boolean isData(byte octect) {
        return (base64Alphabet[octect] != -1);
    }

    public static boolean isBase64(String isValidString) {
        if (isValidString == null)
            return false;
        return (isArrayByteBase64(isValidString.getBytes()));
    }

    public static boolean isBase64(byte octect) {
        return (isWhiteSpace(octect) || isPad(octect) || isData(octect));
    }

    /**
     * remove WhiteSpace from MIME containing encoded Base64 data. e.g. " sdffferererrereresfsdfsdfsdff\n\r iiiiiiiiierejrlkwjerklwjerwerwr==\n\r"
     * 
     * @param data
     * @return stripped data
     */
    public static synchronized byte[] removeWhiteSpace(byte[] data) {
        if (data == null)
            return null;

        int newSize = 0;
        int len = data.length;
        int i = 0;
        for (; i < len; i++) {
            if (!isWhiteSpace(data[i]))
                newSize++;
        }

        if (newSize == len)
            return data;// return input array since no whiteSpace

        byte[] arrayWithoutSpaces = new byte[newSize];// Allocate new array without whiteSpace

        int j = 0;
        for (i = 0; i < len; i++) {
            if (isWhiteSpace(data[i]))
                continue;
            else
                arrayWithoutSpaces[j++] = data[i];// copy non-WhiteSpace
        }
        return arrayWithoutSpaces;

    }

    public static synchronized boolean isArrayByteBase64(byte[] arrayOctect) {
        return (getDecodedDataLength(arrayOctect) >= 0);
    }

    /**
     * Encodes hex octects into Base64
     * 
     * @param binaryData
     *            Array containing binaryData
     * @return Encoded Base64 array
     */
    public static synchronized byte[] encode(byte[] binaryData) {
        if (binaryData == null)
            return null;

        int lengthDataBits = binaryData.length * EIGHTBIT;
        int fewerThan24bits = lengthDataBits % TWENTYFOURBITGROUP;
        int numberTriplets = lengthDataBits / TWENTYFOURBITGROUP;
        byte encodedData[] = null;

        if (fewerThan24bits != 0) // data not divisible by 24 bit
            encodedData = new byte[(numberTriplets + 1) * 4];
        else
            // 16 or 8 bit
            encodedData = new byte[numberTriplets * 4];

        byte k = 0, l = 0, b1 = 0, b2 = 0, b3 = 0;

        int encodedIndex = 0;
        int dataIndex = 0;
        int i = 0;
        if (fDebug) {
            System.out.println("number of triplets = " + numberTriplets);
        }
        for (i = 0; i < numberTriplets; i++) {

            dataIndex = i * 3;
            b1 = binaryData[dataIndex];
            b2 = binaryData[dataIndex + 1];
            b3 = binaryData[dataIndex + 2];

            if (fDebug) {
                System.out.println("b1= " + b1 + ", b2= " + b2 + ", b3= " + b3);
            }

            l = (byte) (b2 & 0x0f);
            k = (byte) (b1 & 0x03);

            encodedIndex = i * 4;
            byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);

            byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);
            byte val3 = ((b3 & SIGN) == 0) ? (byte) (b3 >> 6) : (byte) ((b3) >> 6 ^ 0xfc);

            encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
            if (fDebug) {
                System.out.println("val2 = " + val2);
                System.out.println("k4   = " + (k << 4));
                System.out.println("vak  = " + (val2 | (k << 4)));
            }

            encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)];
            encodedData[encodedIndex + 2] = lookUpBase64Alphabet[(l << 2) | val3];
            encodedData[encodedIndex + 3] = lookUpBase64Alphabet[b3 & 0x3f];
        }

        // form integral number of 6-bit groups
        dataIndex = i * 3;
        encodedIndex = i * 4;
        if (fewerThan24bits == EIGHTBIT) {
            b1 = binaryData[dataIndex];
            k = (byte) (b1 & 0x03);
            if (fDebug) {
                System.out.println("b1=" + b1);
                System.out.println("b1<<2 = " + (b1 >> 2));
            }
            byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
            encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
            encodedData[encodedIndex + 1] = lookUpBase64Alphabet[k << 4];
            encodedData[encodedIndex + 2] = PAD;
            encodedData[encodedIndex + 3] = PAD;
        } else if (fewerThan24bits == SIXTEENBIT) {

            b1 = binaryData[dataIndex];
            b2 = binaryData[dataIndex + 1];
            l = (byte) (b2 & 0x0f);
            k = (byte) (b1 & 0x03);

            byte val1 = ((b1 & SIGN) == 0) ? (byte) (b1 >> 2) : (byte) ((b1) >> 2 ^ 0xc0);
            byte val2 = ((b2 & SIGN) == 0) ? (byte) (b2 >> 4) : (byte) ((b2) >> 4 ^ 0xf0);

            encodedData[encodedIndex] = lookUpBase64Alphabet[val1];
            encodedData[encodedIndex + 1] = lookUpBase64Alphabet[val2 | (k << 4)];
            encodedData[encodedIndex + 2] = lookUpBase64Alphabet[l << 2];
            encodedData[encodedIndex + 3] = PAD;
        }
        return encodedData;
    }

    /**
     * Decodes Base64 data into octects
     * 
     * @param base64Data
     *            Byte array containing Base64 data
     * @return Array containind decoded data.
     */
    public static synchronized byte[] decode(byte[] base64Data) {

        if (base64Data == null)
            return null;

        byte[] normalizedBase64Data = removeWhiteSpace(base64Data);

        if (normalizedBase64Data.length % FOURBYTE != 0) {
            return null;// should be divisible by four
        }

        int numberQuadruple = (normalizedBase64Data.length / FOURBYTE);

        if (numberQuadruple == 0)
            return new byte[0];

        byte decodedData[] = null;
        byte b1 = 0, b2 = 0, b3 = 0, b4 = 0, marker0 = 0, marker1 = 0;
        byte d1 = 0, d2 = 0, d3 = 0, d4 = 0;

        // Throw away anything not in normalizedBase64Data
        // Adjust size
        int i = 0;
        int encodedIndex = 0;
        int dataIndex = 0;
        decodedData = new byte[(numberQuadruple) * 3];

        for (; i < numberQuadruple - 1; i++) {

            if (!isData((d1 = normalizedBase64Data[dataIndex++])) || !isData((d2 = normalizedBase64Data[dataIndex++]))
                    || !isData((d3 = normalizedBase64Data[dataIndex++])) || !isData((d4 = normalizedBase64Data[dataIndex++])))
                return null;// if found "no data" just return null

            b1 = base64Alphabet[d1];
            b2 = base64Alphabet[d2];
            b3 = base64Alphabet[d3];
            b4 = base64Alphabet[d4];

            decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);
            decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
            decodedData[encodedIndex++] = (byte) (b3 << 6 | b4);
        }

        if (!isData((d1 = normalizedBase64Data[dataIndex++])) || !isData((d2 = normalizedBase64Data[dataIndex++]))) {
            return null;// if found "no data" just return null
        }

        b1 = base64Alphabet[d1];
        b2 = base64Alphabet[d2];

        d3 = normalizedBase64Data[dataIndex++];
        d4 = normalizedBase64Data[dataIndex++];
        if (!isData((d3)) || !isData((d4))) {// Check if they are PAD characters
            if (isPad(d3) && isPad(d4)) { // Two PAD e.g. 3c[Pad][Pad]
                if ((b2 & 0xf) != 0)// last 4 bits should be zero
                    return null;
                byte[] tmp = new byte[i * 3 + 1];
                System.arraycopy(decodedData, 0, tmp, 0, i * 3);
                tmp[encodedIndex] = (byte) (b1 << 2 | b2 >> 4);
                return tmp;
            } else if (!isPad(d3) && isPad(d4)) { // One PAD e.g. 3cQ[Pad]
                b3 = base64Alphabet[d3];
                if ((b3 & 0x3) != 0)// last 2 bits should be zero
                    return null;
                byte[] tmp = new byte[i * 3 + 2];
                System.arraycopy(decodedData, 0, tmp, 0, i * 3);
                tmp[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);
                tmp[encodedIndex] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
                return tmp;
            } else {
                return null;// an error like "3c[Pad]r", "3cdX", "3cXd", "3cXX" where X is non data
            }
        } else { // No PAD e.g 3cQl
            b3 = base64Alphabet[d3];
            b4 = base64Alphabet[d4];
            decodedData[encodedIndex++] = (byte) (b1 << 2 | b2 >> 4);
            decodedData[encodedIndex++] = (byte) (((b2 & 0xf) << 4) | ((b3 >> 2) & 0xf));
            decodedData[encodedIndex++] = (byte) (b3 << 6 | b4);

        }

        return decodedData;
    }

    /**
     * returns length of decoded data given an array containing encoded data. WhiteSpace removing is done if data array not valid.
     * 
     * @param base64Data
     * @return a -1 would be return if not
     */
    static public synchronized int getDecodedDataLength(byte[] base64Data) {

        if (base64Data == null)
            return -1;

        if (base64Data.length == 0)
            return 0;

        // byte[] normalizedBase64Data = removeWhiteSpace( base64Data );//Remove any whiteSpace
        byte[] decodedData = null;

        if ((decodedData = decode(base64Data)) == null)// decode could return a null byte array
            return -1;

        return decodedData.length;
    }
}
